A photodetector is sometimes used to sense the light produced by a light source. The sensed light may then be used to regulate the intensity or color of light produced by the light source. If the incident light on the photodetector is too great, the photodetector can saturate. That is, if the incident light on the photodetector is too great, the photodetector may become unable to distinguish between different intensities of incident light. When this happens, the photodetector may not regulate the light source correctly, or may fail to regulate the light source at all.
The likelihood that a photodetector will saturate can be reduced in a variety of ways. One way is to carefully position or orient the photodetector with respect to the light produced by a light source. For example, the photodetector may be placed closer to, or farther from, the light source; or, the photodetector may be oriented perpendicular to, or parallel to, the light produced by the light source.
Another way to keep a photodetector from saturating is to place one or more neutral density filters over the photodetector.
Yet another way to keep a photodetector from saturating is to regulate the light produced by a light source to ensure that the incident light on the photodetector never exceeds a predetermined threshold. This, however, can have the undesirable effect of artificially limiting the light output of the light source.